The technology of segmented ball valves is well developed. Typically, a segmented ball valve includes a hollow valve body which has a throughput or flow passageway and has attached thereto, flange members for coupling to a pipe or conduit. In the valve body, a rotatable segmented ball valve element is rotatably mounted to move between a position closing the passageway to fluid flow and a position permitting full bore fluid flow through the passageway. The segmented ball valve element is rotatively mounted by virtue of a lower rotative pinion mounting of the valve element to the valve body and an upper rotatable shaft mounting which extends to the exterior of the valve body so that rotative motion can be imparted to the shaft by a wrench or the like.
While there are a variety of specific valve applications and varieties of valves, it is highly common that the valve element seal against an annular elastomer and/or teflon or resilient sealing member and/or some sort of metal-to-metal contact seal. When the valve element is in a closed position, substantial pressure differential can exist across the sealing surface of the valve element and the sealing member.
While the prior art has suggested use of eccentric pinions and shafts for the mounting of valve members, it has not heretofore utilized eccentric mounting of the pinion and shaft for a segmented ball valve member in connection with a sealing system wherein three (3) distinct gradients of sealing can be accomplished with the sealing mechanism as a function of the turning torque on the valve element.